1. Field of the Invention
The present invention relates to a bending apparatus which is mountable in, for example, an insertion section of an endoscope and includes a shape sensor for detecting a bending direction/curvature.
2. Description of the Related Art
Japanese Patent No. 4714570 discloses a shape detection probe which is assembled in a scope of an endoscope, bends as one-piece with the scope of the endoscope, and is used for detecting the shape of the scope. In this kind of shape detection probe, detection light, which is light for curvature detection and is emitted from a light source, is transmitted to a distal end through a light-supplying fiber. A mirror is provided at an emission end of the light-supplying fiber. Reflective light of the detection light, which is reflected by the mirror, is incident on a curvature detection fiber, and is received by a light reception element. A plurality of light loss portions, which absorb part of the reflective light, are provided near the surface of the curvature detection fiber. An absorption amount of the reflective light by the light loss portions varies depending on the curvature of a fiber bundle at locations where the light loss portions are provided. Thus, Japanese Patent No. 4714570 discloses a structure in which the curvature of the fiber bundle is calculated based on the intensity of the reflective light before and after the reflective light passes through the light loss portions.